Engine dies uphill!!! (Don't laugh)

[Wags]

When it comes to jets, should a number 80 or 82 read .80 or .82 when measured? Or do the numbers just reflect the next size up or down for whatever brand your useing? I ask because I have 3 different number 75 jets and three diferent size drill bits fit in each one. Close but not the same.

 

[Wags]

So yeah, i made a little bit of progress today. Out of the hole it runs great, A little sluggish in the middle which is all jet needle. I couldn't even get to midrange when I started. The main jet is still a little lean because when I back off the throttle a touch I get more acceleration. I find that amazing because I have drilled a .86 hole in the main jet. I went up one size at a time and each time everything got better. Thing is C clip is in its lowest position and is the only place that I have any mid-range. I tried raising the c-clip from there after rejetting and all I get is a bog and will not allow me to get into mainjet land. I will go up one more hole size tomorrow and hopefully that gives me a little more adjustability on my jet needle.

 

[gary55]

When it comes to jets, should a number 80 or 82 read .80 or .82 when measured? Or do the numbers just reflect the next size up or down for whatever brand your useing? I ask because I have 3 different number 75 jets and three diferent size drill bits fit in each one. Close but not the same.

The #'s on the jets should represent the orifice diameter in 100ths of a mill. If you order them from SBP they are in my experience correct. Ebay jets are notorious for incorrect sizing.

 

[Street Ryderz]

You have a cns-r carb, a slightly different type, it doesn't have oil injection ports, or so they say, apparently they don't have breathers either, and I don't think I've had a chance to inspect one...

Chances are if you put your finger over it and it calms down then you should cap it.

A Cns isn't a Mikuni clone but I see the resemblance. It's a kaibao brand carb that was copied a bunch of times by different companies, they work on anything from a 66cc ht motor to a yz80 and even 100cc bikes, they only have like a 15mm throat so you wouldn't want to go much bigger than 100cc on it.

You can buy them by the thousand on alibaba right here:
https://m.alibaba.com/product/60287...&type=product&detailId=60287035245&redirect=1

I only like them because they are cheaply found, work on a large group of motors, and have all the right adjustments. Litteraly capable of being tuned to just about anything under 100cc, with or without oil injection.

Beats me where the actual design came from, may have been a generic carb somebody needed made by the millions that wouldn't break some patent or something. They work I like them.

Actually the one he and I have are more like 16.5 mm stock thru the body!I bored mine out to 17.5mm and am thinking about going to 18mm but then that would be the max the body would allow. It is a good tunable carb for cheap but you have to take the time to set it up right and know how to do it !

 

[Street Ryderz]

So yeah, i made a little bit of progress today. Out of the hole it runs great, A little sluggish in the middle which is all jet needle. I couldn't even get to midrange when I started. The main jet is still a little lean because when I back off the throttle a touch I get more acceleration. I find that amazing because I have drilled a .86 hole in the main jet. I went up one size at a time and each time everything got better. Thing is C clip is in its lowest position and is the only place that I have any mid-range. I tried raising the c-clip from there after rejetting and all I get is a bog and will not allow me to get into mainjet land. I will go up one more hole size tomorrow and hopefully that gives me a little more adjustability on my jet needle.

You drilled it to .86mm ? if so thats getting pretty big but quite possible with the reed setup,as I said before I run an #82 in the summer in mine being a pp engine and if I bore it the last .5mm im sure I will have to go up again!You can put the needle in a dremel or rotary tool and reshape the taper on the needle if needed to dial in the mid range reducing the dia slightly from the bottom(tip)up about 3/4 of the way to the transition to the fixed dia or the angle before the flat does make a big difference so just like drilling the jet do alittle and try it and so on.